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Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid - VCE - SSCE Chemistry - Question 1 - 2003 - Paper 1
Question 1
Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid. a. What is meant by the term ‘saturated’? b. Stearic acid can be used as a source of energy. ... show full transcript
Worked Solution & Example Answer:Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid - VCE - SSCE Chemistry - Question 1 - 2003 - Paper 1
Step 1
What is meant by the term ‘saturated’?
Answer
The term ‘saturated’ refers to fatty acids that contain no double bonds between the carbon atoms in their hydrocarbon chain. This means that all carbon atoms are fully 'saturated' with hydrogen atoms, resulting in a straight structure that can pack tightly together, typically leading to a solid state at room temperature.
Step 2
Write a chemical equation for the complete reaction between oxygen and stearic acid.
Answer
The combustion of stearic acid can be represented by the following balanced chemical equation:
ightarrow 18 ext{CO}_2 + 18 ext{H}_2 ext{O}$$ In this reaction, stearic acid reacts with oxygen to produce carbon dioxide and water.Step 3
Step 4
How does the additive prevent oils becoming rancid?
Answer
Antioxidants prevent oils from becoming rancid by inhibiting the oxidation process. They work by reacting preferentially with free radicals and preventing them from initiating the breakdown of fats. This helps to maintain the stability and quality of the oil over time.